Use EINVAL instead of ENOENT

src/scheme/debug.rs

src/scheme/env.rs

src/scheme/event.rs

src/scheme/initfs.rs

src/scheme/irq.rs

src/scheme/live.rs

src/scheme/null.rs

src/scheme/pipe.rs

src/scheme/root.rs

src/scheme/sys/mod.rs

src/scheme/time.rs

src/scheme/zero.rs